package saima;

import java.util.Scanner;

/**
 * @author MaoLin Wang
 * @date 2020/4/1711:15
 */
public class 异或 {
    public static void main(String[] args) {
        Scanner scanner=new Scanner(System.in);
        while (scanner.hasNextInt()){
            int n=scanner.nextInt();
            int a=Integer.parseInt(scanner.next(),2);
            int b=Integer.parseInt(scanner.next(),2);
            System.out.println(a^b);
        }
    }
}
